Crankshaft dampers are used to reduce torsional deflections in crankshafts of combustion engines. Crankshaft dampers function by converting torsional deflections into heat which reduces the crankshaft torsional deflections to increase the life of a crankshaft. Crankshaft dampers may be of the elastomeric type or of the viscous fluid type. This disclosure is directed to elastomeric type crankshaft dampers.
Crankshaft dampers are typically attached to the front end of the engine and are normally enclosed in confined spaces. Heat from the engine and other components such as turbochargers, and the like, creates high ambient temperatures in the engine compartment. Heat is also conducted from the engine to the crankshaft damper. The high ambient temperatures and heat conducted by the engine add to the heat created by damping the torsional deflections of the crankshaft.
Elastomeric crankshaft dampers generally include a rigid hub that is secured to the crankshaft. An inertia ring is attached to the hub by an elastomeric member which may be shaped as a ring or a disk. Vibrations of the crankshaft are damped by torsional shearing of the elastomeric member relative to the inertia ring. The inertia of the ring and the torsional spring rate of the elastomeric member are selected to provide a specific natural frequency, at which resonance occurs resulting in maximum heat generation in the crankshaft damper to minimize crankshaft deflection.
All crankshaft dampers, including both viscous and elastomeric crankshaft dampers, have operating temperature limits based on their design and the temperature resistance of the damping materials. Recently released high temperature crankshaft damper elastomers have a higher temperature limit than other types of crankshaft damper elastomers and viscous fluids. However, some applications may exceed the temperature limit of these high temperature crankshaft damper elastomers and, as a result, there is a need for improvements in elastomeric crankshaft dampers to obtain greater heat dissipation.
This disclosure is directed to solving the above problems and other problems as summarized below.